||July 25, 2012 18:36
I'm having a bit of trouble successfully running a hydrogen-air transient combustion case. The basic geometry is a cylinder with a smaller, short concentric cylinder. Oxygen is introduced at the larger cylinder's cross-section while hydrogen is introduced inside of the smaller cylinder and free to flow out. Both are mass flow inlets. I am able to run a steady state simulation and achieve combustion but when I switch over to a transient regime, the mixture never ignites and remains at the species inlet temperature.
I've tried increasing the temperature of both species as to induce ignition but no luck. I've also tried timesteps ranging from 1e-05 to 1e-03 and no luck.
Some solver specifics:
- Species transport and reactions combustion model (Volumetric, Finite Rate/Eddy Dissipation
- k-e realizable turbulence model
- I've used both PISO and SIMPLE pressure-velocity coupling schemes
- All spatial discretization entries are first order upwind
Any help would be greatly appreciated. As I said, steady state works fine with the same solver settings (if applicable). Switching over to transient results in no ignition.